This technology relates to electrical power supply systems, and provides a scalable, general-purpose, power flow calculation method and system that reduces or eliminates non-converging power system voltage stability calculation issues using an advantageous bus type. The system outperforms the conventional calculation method where the power flow solution diverges due to ill-conditioning at high levels of power transfer. This technologys reformulated power flow configuration provides a new parameterization to eliminate the ill-conditioning issue in the power systems voltage stability calculation, improving its overall performance and operational cost. This technology utilizes an AQ bus for voltage stability analysis instead of the conventional PQ-bus type that typically results in numerical ill-conditioning near the point of maximum power transfer.